economics 功課

In a perfect competitive market, there are many sellers and buyers and all of them have perfect information on prices and all goods are homogeneous. Therefore, if one of the seller raise the price of the goods, he or she can not sell those goods as buyers will go elsewhere to purchase the homogeneous goods. Therefore, a same unit price is being charged for same goods and the selling price becomes the marginal revenue (the additional revenue obtained by selling one additional unit of goods)